The present invention relates to a vehicle seat assembly and in particular to a seat assembly having a manually operated seat back recliner and a single position memory dump mechanism for locking the seat back in a predetermined set position upon return of the seat back from a forward dump position.
Vehicle seat assemblies, particularly those adapted for use in the front seat of a two-door motor vehicle, are often equipped with a dump feature that enables the seat back to be rotated about a transverse axis from a normal use position to a forward "dump" position to improve access to the rear seat area of the vehicle. In addition, many seat assemblies are equipped with a recliner mechanism that enables the angle of the seat back to be adjusted within a defined range of use positions. This range is bounded by a front use position and a rear use position. The recliner operates to lock the seat back in place to hold the seat back in the adjusted position. The dump feature typically operates upon release of the recliner to hold the recliner released, allowing the seat back to rotate forward.
For convenience while rotating the seat back to the forward dump position and during return of the seat back, most recliner mechanisms are typically held released so that they do not lock. By not locking, the seat back is free to rotate between the front use position and the dump position without the necessity of manually holding the recliner operating lever in a release position. Once the seat back has moved forward beyond the front use position, the recliner operating lever can be released. Return of the seat back to a use position is accomplished by merely pushing the seat back rearward.
Various approaches have been utilized in locking the seat back once it is returned to a use position. One approach is to lock the recliner when the seat back has been returned to the front use position. While this approach is simple, the seat back will lock in a position which is uncomfortable and which is awkward for most people to sit in the seat assembly.
Another approach has been to provide a full memory feature in which the recliner will only lock when the seat back has been returned to its adjusted use position prior to being dumped forward. Such a full memory feature, while being convenient for the user, is relatively complex and thus costly to produce.
It is an object of the present invention to provide a manual seat recliner with a single position memory which locks the seat back in a set position rearward of the front use position that is comfortable for most seat occupants.
The seat assembly of the present invention includes a cam mounted to the rotating seat back and a cam follower coupled to the recliner operating lever for holding the operating lever in the release position as the seat back is rotated forward to the dump position. The cam has a first surface portion engagable with the follower as the seat back is rotated from the front use position to the dump position and a second surface portion engagable with the follower as the seat back is returned from the dump position to the set position. Both surface portions of the cam are substantially concentric with the seat back pivot axis. The second surface portion has a greater circumferential or angular extent than the first portion, maintaining the follower in contact with the cam for a greater angular travel of the seat back. This increase in angular seat back travel is between the front use position and the set position, several degrees further rearward. As a result, the recliner does not lock the seat back until the seat back has been returned to the set position.